Strip line power harness



May 16, 1967 J. J. KAREW ETAL 3,320,438

STRIP LINE' POWER HARNESS Original Filed March 28, 1963 5 s ee seet 1fl/ I 2 v INVENTORS. ig/ mamas" BY JAMES E. JONES waeam l8 nw AGENT May16, 1967 J. J. KAREW ETAL STRIP LINE POWER HARNESS 5 Sheets-Sheet 2Original Filed March 28, 1963 llll'llllllllfll'llllllllll'l momINVENTOR. JOSEPH J. KAREW HARRY W. HESS JKHES E. JONES 011% R mac:

AGENT y 1967 J. J. KAREW ETAL 3,320,488

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STRIP LINE POWER HARNESS Original Filed March 28, 1963 5 Sheets-Sheet 5LTJQ:

INVENTORS. JOSEPH JQKAREW HARRY w. HESS BY JAMES E. JONES AGENT UnitedStates Patent 3,320,488 STRIP LINE POWER HARNESS Joseph J. Karew,Warminster, Harry W. Hess, Norristown, and James E. Jones, Malvern, Pa.,assignors to Burroughs Corporation, Detroit, Mich, a corporation ofMichigan Continuation of application Ser. No. 268,771, Mar. 28, 1963.This application July 26, 1966, Ser. No. 568,059 Claims. (Cl. 317-401)This application is a continuation of application Ser. No. 268,771,filed Mar. 28, 1963, now abandoned.

This invention relates to power supply apparatus for distributing D.C.voltages from a power source to a utilizing load and more particularly,to power distribution apparatus for a digital computer system.

The source impedance, presented to a load utilizing means in a computersystem consists of the combined power supply impedance and thedistributed resistance, inductance and capacitance of the connectingdistribution voltage leads. For low frequency load currents, theconnecting leads may present an insignificant reactive loss; however, asthe operating frequency increases this line loss increases and resultsin degraded regulation and marginal computer operation. The recentadvances in high speed computer technology requires that very lowimpedance voltage connecting lines he used. Essentially, the highfrequency loads dictate the need for extremely low impedancedistribution lines with low inductance and high capacitance and highlyconductive power lines. In this respect, conventional wiring techniquesutilizing wires of round cross-section can only solve the DC. conductiveproblems while flattened strip lines separated by thin dielectricmaterial sandwiched between ground strips guarantee a minimum inductanceand a maximum distributed capacitance. Essentially, the characteristicimpedance (at high frequencies) is determined by the followingrelationship Z (L/C) where Z =the characteristic impedance L=distributedinductance per unit length C=distributed capacitance per unit length Itis an object of this invention therefore to provide an improved powersupply apparatus for a computer system which avoids one or moredisadvantages of the prior art arrangements and which has an improvedconductivity.

It is a further object of this invention to provide a novel power supplyapparatus for a computer system having an improved high frequencyconductivity.

In accordance with a preferred form of the invention in a computersystem, power supplies and power distribution apparatus are provided.Each cabinet or housing of the system has its own complete power supplyand control system. One portion of the power supply is connected with areceptacle and from this receptacle two groups of flat ribbon-likevoltage busses with their external surfaces insulated, each extend intoa movable module or rack which may be hingedly mounted. A plurality ofinsulated ground shields generally of the like outline form as thevoltage busses are cemented top and bottom to each group and are alsointerleaved and cemented between adjacent voltage busses of the group bymeans of an electrically conductive cement. The ground shields aregrounded at one end to the cabinet adjacent said receptacle and extendinto the hinged logic card racks for suitable connection at theiropposite ends. Each group of voltage busses thus feed power to circuitscarried by said printed circuit cards.

For a better understanding of the invention, together with other andfurther objects thereof, reference is had to the following descriptiontaken in conjunction with the accompanying drawings and its scope will'be pointed out in the appended claims.

FIG. 1 is a perspective view of a computer cabinet in its open positionand showing logic card folding racks or modules hinged to the computercabinet frame;

FIG. 2 is a plan view of the cabinet in its closed position, partiallyin section with the topmost portion of the cabinet removed and showingthe racks in their closed position;

FIG. 3 is a front elevational view of the cabinet with- FIG. 8A is asectional view taken along the lines.

8A8A of FIG. 8;

FIG. 8B is a sectional view taken along the line 8B-8B of FIG. 8;

FIG. 9 is a schematic composite view of a typical ground shieldgenerally similar to the voltage bus shown in FIG. 8;

FIG. 9A is a sectional view taken along line 9A-9A of FIG. 9;

FIG. 9B is a sectional view taken along the line 9B-9B of FIG. 9;

FIG. 10 is a sectional view along the lines 10-10 of FIG. 5 removed;

FIG. 11 is a pictorial view looking in the direction of the arrow 11 inFIG. 2;

FIG. 11A is a sectional view taken along the line 11A11A of FIG. 11.

Referring to FIGS. 1 and 3 of the drawings, there is shown a computercabinet 10 with its front panel 12 hinged to its open position aboutaxis 13. A pair of rack assemblies 15 and 17 hinged about axis 19 alongthe showing the insulation on the ground strips opposite side of thecabinet include tiers of printed circuit.

cards 21, which are supported by transverse guide plates 23. These cardscarry the logic circuitry for the computer system.

Interiorly of each cabinet, FIG. 2, there is provided a DC. power supply25 which is fed to the aforementioned printed circuit cards by means ofa power harness assembly 27 designated schematically in heavy blacksolid and dotted lines. In the present embodiment of the invention thepower harness assembly comprises two groups designated 27A and 27B, theformer being fed to the front rack 15 and the latter to the rearmostrack 17. The power harness includes a DC. receptacle 29 connected to thepower source 25 and transverse harness sections 36A and 3013 whichextend within the racks 15 and 17. The two groups of said power harness27A and 27B extending in parallel from the receptacle 29 which receivespower from said power supply, are cemented by means of an electricallyconductive cement 31 to back wall 32, and to the left side wall 33. Eachgroup then separates one from the other, to face and pass through theZ-shaped rack side rail members 28, to feed the tiers of printed circuitcards 21 in their respective racks 15, 17. A suitable clamp 34 fastensboth groups of the assembly to the side wall 33.

Since both power harness groups 27A and 27B are generally similar indetail, a discussion of one will sufiice for the other. By way ofexample, the power harness group designated 27A is made up of a seriesof flat copper voltage busses 37 indicated in outline form in FIG. 8,stacked one upon another but separated by a series of ground shields 39of the same general outline form as shown in FIG. 9. A pair of groundshields 39 in addition sandwich the entire groups so that each voltagebus has a ground shield electrically cemented in contact with one of itsopposite fiat faces throughout substantially its entire length, as willbe described in greater detail hereinafter.

Referring now to FIG. 8, each voltage or power bus 37 includes ahorizontal feeder belt portion 41, which is routed along the rear andside walls of the cabinet, a large vertical portion 42 of which ispositioned within the Z-shaped rack side rail member 28, and a pluralityof transverse power distribution segments 45 and 46 which includecomb-like finger portions 47 suitably spaced along the length of saidsegments. In order to permit flexing action of the feeder belts when therack members 15 and 17 are pivoted about the common hinge axis 19, thefeeder belt portion 41, FIG. 8, may be made of multiple ply sheet copperas shown in FIG. 8A. The external surfaces of the two ply feeder beltportion is suitably insulated as at 44. The central bus portion 42 isshown in the form of a heavy single ply copper and similarly insulatedas at 43. The bus portion is then joined to the bearing portion by meansof brass eyelets 48 with the internal facing surfaces suitably soldered.Additional insulation 49 is thereafter applied to the joint so formed.With reference to FIG. 8B the transverse power harness 46, from whichfingers 47 extend, may be joined for example as by soldering to thecentral heavy vertical section 42 and the electrical joint so formed mayalso be insulated as at 49. The remaining external surface of theharness 46 is insulated as at 44.

With reference to FIGS. 9 and 9A, the horizontal feeder belt portion 53of the ground shield 39 engages in facing contact the feeder belt busportion 41 as will be later described and is likewise routed from alongthe rear and side walls 32, 33 of the cabinet 10. In order to facilitateflexure due to the hinging action of the racks, portion 53 is likewiseformed of two ply sheet copper and is insulated as at 55. It issimilarly electrically connected to the vertical ground shield portion56 as by brass eyelets 57 and solder. The vertical ground shield 56 itis noted, is of less thickness than the voltage bus portion 42 and isprovided with insulation 58 at its external surfaces. The brasseyelet-solder connection so formed is likewise insulated as at 59. Alongthe opposite edge of central ground shield 56, a plurality ofhorizontally disposed portions 61 of sheet copper are suitably connectedthereto as by soldering in the manner as indicated in FIG. 9B. Thislatter connection is also properly insulated as at 62 for example, as bytape, to protect the same when interleaved between voltage bus portions42 in the manner hereafter to be described. It should be noted that thetransverse portions 61 do not include portions which correspond tofingers 47 of the transverse power distribution segments 45, 46 of FIG.8.

Each of the harness groups 27A, 27B made up of ground shields 39 ofoverall outline form as shown in FIG. 9, and voltage busses 37 ofoutline form as shown in FIG. 8, are superimposed and cemented togetherby electrically con-- ductive cement in alternate ground shield andvoltage bus layers. The build-up of the layers as illustrated in FIGS. 6and 10, is as follows: commencing first with the transverse printedcircuit socket supporting plate 65, the first layer of material of saidpower harness is an uninsulated transverse ground shield strip segment61. This may be cemented in position to the plate by means of anelectrically conductive cement 31. The purpose of this is to both holdthe strips in place physically and to give a low impedance ground. Thenext adjacent layer electrically cemented thereto is the segment of thetransverse voltage bus harness 45 which is of single ply insulatedcopper as previously described. The third layer from said supportingplate is another ground shield segment 61, and the fourth layer, avoltage bus segment 45, and so forth, all cemented together by means ofan electrically conductive cement and concluding with a ground shieldsegment 61 as the outside layer.

This alternate ground shield-voltage bus array may be observed also inconnection with FIG. 7 which represents a cross-sectional view takenthrough the feeder belt section of each harness group. Thus theinsulated two-ply feeder belt ground segment 53, FIG. 9, is showncemented by means of an electrically conductive cement into contactingengagement with the Z-shaped hinge side rail 28 of the printed circuitcard rack 15, while the next adjacent layer is that of the feeder beltvoltage bus portion 41, of FIG. 8. Successive layers outwardly from saidhinge rail consist of ground shield 53 and voltage bus layers 41 etc.,to terminate with an outermost ground shield layer 53. As seen in FIGS.4 and 6, the central portion of the entire harness group 27A made up inalternate layers as described, is secured to the inner hinge side railby means of suitable clips 71, and by top and bottom brackets 72, FIG.4. As indicated in the last named figure,

the feeder belt portion of the power harness group 27A lies below thefeeder belt portion of group 27B, and are so routed along the side wall33 and back Wall 32 of the cabinet 10, to the D.C. power supply 25.

With reference to FIG. 11, the feeder belt portions of the ground shieldsegments 53 of each of the groups 27A and 27B which are in surfacecontacting engagement with the back wall 32 of said cabinet areelectrically connected by means of a pair of solder strips 75 whichtransversely bridge said endmost ground shield portions. The insulatedvoltage busses 41 which lie on top of said lowermost contacting groundstrips 53 pass beyond the solder strip 75 and are terminated short ofthe receptacle 29. As seen in FIG. 11A the insulation 44 is removed anda solder bent end strip 77 is folded over the ends so exposed andconductive wires 78 are passed therethrough and joined to the conductorpins 79 of receptacle 29. An insulative layer 80 is then applied overthe bent end strip 77 and wire 78 to prevent the same from shorting out.Thereafter the secondmost ground shield feeder belt segments from saidback cabinet wall are likewise bridged by a second set of transversesolder strips 75 while the voltage feed bus segments which lie on top ofsaid second ground strips are connected similarly by wires 78, to saidplus 79 of said receptacle. The remaining layers are secured similarlyby solder strips which are all aligned in superimposed relation and arethen suitably drilled and secured to the cabinet wall 32 by ground studs81. The remaining like spaced voltage feeder belt portions from saidback cabinet wall of both of said groups 27A, 27B are connected by loopsof wire as at 83.

With reference now to FIGS. 5 and 6, it can be seen that the printedcircuitry previously referred to comprising the plurality of printedcircuit boards 21, have mounted thereupon electrical components 87, 88which employ high frequency A.C. and are of the type employed in presentday computer systems FIG. 6. Rows of said printed circuit boards aresupported transversely of said racks 15 and 17 as previously describedby means of supporting shelves 23 having elongated apertures 91.

The material around each aperture is turned to form lips 92 with top andbottom shelf portions to thereby provide a series of U-shaped guides toposition each card in its proper location. The transverse socketsupporting plate 65 also includes apertures as at '95 to receive in eacha printed circuit socket 94. The latter include springlike contacts 96which engage contact pads 97 of said printed circuit boards to grip theprinted circuit boards in place. Free ends of selected contacts 96 areconnected to the uninsulated finger-tip portions 50 of fingers 47 ofsaid voltage bus harness portions 45, 46 to thereby provide said printedcircuit boards with sources of D.C. voltage. Since each group 27A, 27Bof said power harness includes a plurality of layers of voltage busses,it should be noted that each such layer may be of a different voltagelevel. Moreover, since the ground shield busses extend the full lengthof the voltage busses, i.e., from the source to the point of utilizationat the printed circuit sockets 94, there is no impedance discontinuity.

From the above description it is seen that in a computer employing highfrequency circuitry that there has been provided a low impedance, lowinductance, highly conductive and adequately insulated and shieldedpower distribution system. Such a system of this type is mandatory incertain types of high speed computers. Although DC. power istransmitted, a low impedance is necessary to eliminate certain adverseeffects. By employing the flat, wide strip line power distribution meansas above described, in a present day high frequency computer system,highly satisfactory results have been achieved.

What is claimed is:

1. In a power supply apparatus for providing low inductance, lowimpedance, power distribution from a power source to a power utilizingmodule, the latter having a frame for supporting a plurality of printedcircuit card utilizing means, the combination comprising:

a rack assembly including means hinged and swingably movable betweenopen and closed positions about the axis of the hinge;

a plurality of rows of printed circuit utilizing means supported withinand disposed transversely of the hinge axis of said rack assembly;

electrical power source means supported within said cabinet;

power harness means for supplying power from said source to said printedcircuit utilizing means in cluding a plurality of layers of relativelyflexible, relativcly thin, flat, elongated, electrically conductiveuninsulated ground conductor busses having horizontal feeder beltportions, vertical portions orthogonally arranged relative to saidfeeder belt portions, and a plurality of segments extending parallel tosaid horizontal portions; and a plurality of layers of relativelyflexible, relatively thin, flat, elongated, electrically insulated powerconductor busses having horizontal feeder belt portions, verticalportions orthogonally arranged relative said feeder belt portions, and aplurality of power distribution segments parallel to said horizontalportions;

each said electrically insulated power conductor bus being insertedbetween a pair of said layers of ground conductor busses therebyconstituting an alternate power conductor and ground unitary assemy;

said assembly being routed along the walls of said rack assembly andsecured to and along the hinge area of said rack assembly, and connectedat its one end to said power supply and continuously extending from saidpower supply to said circuit utilizing means passing along said hingearea and having certain of the opposite ends of the power distributionsegments connected to said circuit utilizing means so that said unitaryassembly provides a plurality of continuous shielded power paths capableof flexing back and forth in the manner of a hinge when said hingedmeans is moved.

2. In a power supply apparatus for providing low in ductance, lowimpedance, power distribution from a poW- or source to a power utilizingmodule, the latter having a frame for supporting a plurality of printedcircuit card utilizing means, the combination comprising:

a cabinet;

a rack assembly including frame means hinged to said cabinet andswingably movable between open and closed positions about the axis ofthe hinge;

a plurality of rows of printed circuit utilizing means supported withinand disposed transversely of the hinge axis of said rack assembly;

electrical power source means supported within said cabinet;

power harness means for supplying power from said source to said printedcircuit utilizing means including a plurality of layers of relativelyflexible, relatively thin, flat, elongated, electrically conductiveuninsulated ground conductor busses. having horizontal feeder beltportions, vertical portions orthogonally arranged relative to saidfeeder belt portions, and a plurality of further portions parallel tosaid horizontal portions; and a plurality of layers of relativelyflexible, relatively thin, flat, elongated, electrically insulatedpo'wer conductor busses having horizontal feeder belt portions, verticalportions orthogonally arranged relative said feeder belt portions, and aplurality of power distribution portions parallel to said horizontalportions, each said electrically insulated power conductor bus beinginserted between a pair of said layers of ground conductor busses;

means connecting together said layers of ground busses and power busseseffectively forming the same into an alternate power conductor andground unitary assembly;

said unitary assembly being cemented to and along the hinge area of saidrack assembly, and connected at its one end to said power supply andextending continuously from said power supply along said hinge area tosaid circuit utilizing means and having the power distribution portionsconnected to said circuit utilizing means, said unitary assembly beingcapable of bending back and forth in the manner of a hinge when saidframe means is moved from open to closed position.

3. The invention in accordance with claim 2 wherein said powerdistribution portions extend between each row of printed circuitutilizing means and each one of such portions further includes integralcomb-like finger members normal to said power distribution portions andprojecting between and extending parallel to said printed circuit meansfor electrical connection with the contacts of said printed circuitutilizing means.

4. In power supply apparatus for providing low inductance, lowimpedance, power distribution from a power source to a power utilizingmodule, the latter having a frame for supporting a plurality of printedcircuit card utilizing means, the combination comprising:

a cabinet;

a rack assembly hinged to said cabinet and movable between open andclosed positions about the axis of the hinge;

a plurality of rows of printed circuit utilizing means supported withinand disposed transversely of the hinge axis of said rack assembly;

electrical power source means supported within said cabinet;

power harness means for supplying power from said source to said printedcircuit utilizing means at least a portion of which extends parallel tothe hinge axis of said rack assembly;

said power harness means including a plurality of layers of relativelyflexible, thin, flat, elongated, electrically conductive, uninsulatedground conductor busses and a plurality of relatively flexible, thin,flat, elongated, electrically conductive power busses, each power bushaving a pair of opposed electrically insulated faces;

each said electrically insulated power bus being inserted between a pairof said layers of ground conductor busses effectively separating thesame and providing a high capacitive alternating power conductor andground unitary assembly;

each said electrically conductive bus and ground conductor bus includinga first portion normal to said hinge axis, a second portion parallel tosaid hinge axis and a third portion integral with said second portion atright angles to said second portion and arranged to form a plurality ofindividual comb- 7 8 like finger projections of appropriate length to beand power busses into an alternate power conductor and positioned inexact juxtaposition to said printed cirground unitary assembly is anelectrically conductive cuit utilizing means; cement effective both tohold the layers in place physicalsaid unitary assembly beingconductively secured to ly and provide a low impedance ground for saidpower the hinge area of said rack assembly, and connected 5 supplyapparatus at its one end to said power supply and extending from saidpower supply to said circuit utilizing means No references cited. alongsaid hinge area and having the third integral portions connected to saidcircuit utilizing means. ROBERT K. SCHAEFER, Primary Examiner.

5. The invention in accordance with claim 2 wherein 10 the meansconnecting together said layers of ground busses SCOTT Assistant Exammer

1. IN A POWER SUPPLY APPARATUS FOR PROVIDING LOW INDUCTANCE, LOWIMPEDANCE, POWER DISTRIBUTION FROM A POWER SOURCE TO A POWER UTILIZINGMODULE, THE LATTER HAVING A FRAME FOR SUPPORTING A PLURALITY OF PRINTEDCIRCUIT CARD UTILIZING MEANS, THE COMBINATION COMPRISING; A RACKASSEMBLY INCLUDING MEANS HINGED AND SWINGABLY MOVABLE BETWEEN OPEN ANDCLOSED POSITIONS ABOUT THE AXIS OF THE HINGE; A PLURALITY OF ROWS OFPRINTED CIRCUIT UTILIZING MEANS SUPPORTED WITHIN AND DISPOSEDTRANSVERSELY OF THE HINGE AXIS OF SAID RACK ASSEMBLY; ELECTRICAL POWERSOURCE MEANS SUPPORTED WITHIN SAID CABINET; POWER HARNESS MEANS FORSUPPLYING POWER FROM SAID SOURCE TO SAID PRINTED CIRCUIT UTILIZING MEANSINCLUDING A PLURALITY OF LAYERS OF RELATIVELY FLEXIBLE, RELATIVELY THIN,FLAT, ELONGATED, ELECTRICALLY CONDUCTIVE UNINSULATED GROUND CONDUCTORBUSSES HAVING HORIZONTAL FEEDER BELT PORTIONS, VERTICAL PORTIONSORTHOGONALLY ARRANGED RELATIVE TO SAID FEEDER BELT PORTIONS, AND APLURALITY OF SEGMENTS EXTENDING PARALLEL TO SAID HORIZONTAL PORTIONS;AND A PLURALITY OF LAYERS OF RELATIVELY FLEXIBLE, RELATIVELY THIN, FLAT,ELONGATED, ELECTRICALLY INSULATED POWER CONDUCTOR BUSSES HAVINGHORIZONTAL FEEDER BELT PORTIONS, VERTICAL PORTIONS HORIONALLY ARRANGEDRELATIVE SAID FEEDER BELT PORTIONS, AND A PLURALITY OF POWERDISTRIBUTION SEGMENTS PARALLEL TO SAID HORIZONTAL PORTIONS; EACH SAIDELECTRICALLY INSULATED POWER CONDUCTOR BUS BEING INSERTED BETWEEN A PAIROF SAID LAYERS OF GROUND CONDUCTOR BUSSES THEREBY CONSTITUTING ANALTERNATE POWER CONDUCTOR AND GROUND UNITARY ASSEMBLY;